1. Field of the Invention
This invention relates to method and apparatus for printing on linerless labels.
2. Brief Description of the Prior Art
The following patent documents are made of record: U.S. Pat. No. 4,477,305; U.S. Pat. No. 5,487,337; U.S. Pat. No. 5,497,701; U.S. Pat. No. 5,868,893; U.S. Pat. No. 6,585,437; U.S. Pat. No. 6,607,318; Japanese 2004-58553, Feb. 26, 2004; Japanese 2004-58554, Feb. 26, 2004.
In prior art linerless label printers the linerless web, which can be composed of a web of label material with a release-coated printable side and a tacky adhesive on the other side, is fed between a print head and an adhesive-resistant:platen roll. The adhesive contacts the platen roll. The web passes between a print head and the platen roll. The print head exerts pressure on the paper and the platen roll. Because the platen roll is made adhesive-resistant by use of silicone rubber and/or by special coatings, the adhesive of the linerless web does not adhere aggressively to the platen roll unless the platen roll becomes worn or the print head is in pressure contact with the linerless web for an extended period of time. Should either or both of these conditions occur, the web can adhere excessively to the platen roll and when the web is advanced, the web can tend to follow around with the platen roll as the platen roll rotates during printing of the next label. Various ways have been tried to avoid this type of action, for example, picks or scrapers are used as in patents and U.S. Pat. No. 6,585,437, for example. Another way of dealing with this problem is disclosed in LINERLESS ADDENDUM, ©1998 Monarch Marking Systems, Inc. wherein the printer is manually opened to a position where the print head is spaced from the platen roll if the printer will be unused for extended periods of time.